AN APPROACH FOR EVALUATING NUMERIC WATER QUALITY CRITERIA
FOR WETLANDS PROTECTION
by
Cynthia A. Hagley and Debra L. T.aylor
Asci Corporation
Duluth, Minnesota 55804
Project Officer
William D. Sanville
Project Leader
Environmental Research Laboratory
Duluth, Minnesota 55804
DU: BIOL
ISSUE: A
PPAi 16
PROJECT: 39
DELIVERABLE: 8234
July 6, 1991
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ABSTRACT
Extension of the national numeric aquatic life criteria to
wetlands has been recommended as part of a program to develop
standards and criteria for wetlands. This report provides an
overview of the need for standards and criteria for wetlands and
a description of the numeric aquatic life criteria. The numeric
aquatic life criteria are designed to be protective of aquatic
life and their uses for surface waters, and are probably
applicable to most wetland types. This report provides a
possible approach, based on the site-specific guidelines, for
detecting wetland types that might not be protected by direct
application of national numeric criteria. The evaluation can be
simple and inexpensive for those wetland types for which
sufficient water chemistry and species.assemblage data are
available, but will be less useful for wetland types for which
these data are not readily available. The site-specific approach
is described and recommended for wetlands for which modifications
to the numeric criteria are considered necessary. The results of
this type of evaluation, combined with information on local or
regional environmental threats, can be used to prioritize wetland
types (and individual criteria) for further site-specific
evaluations and/or additional data collection. Close
coordination among regulatory agencies, wetland scientists, and
criteria experts will be required.
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CONTENTS
Abstract
Tables
Acknowledgements iv
1. Introduction 1
Need .for standards for wetlands 1
Proposed approach to 'development of vetland
standards 3
Purpose of this document 4
2. Current Surface Water standards and Criteria 6
Description of standards and criteria 6
Development of national aquatic life numeric
criteria • • 7
Site-specific guidelines 8
3. The Need for Evaluating Numeric Water
Quality Criteria: Use of the Site-Specific
Guidelines 9
Overall relevance of criteria to wetlands 9
Wetland variability 10
Use of the site-specific guidelines for
wetlands 10
Aquatic plants 14
4. Evaluation Program 16
Classification 16
Evaluating the appropriateness of direct
application of criteria 17
Developing site-specific criteria 18
5. Example Analyses 19
Example 1 19
Example 2 21
Summary of the example analyses 24
6. Conclusions 26
References 28
Appendices
A. Sources used in species habitat identification
for Minnesota marshes 31
B. Sources used in species habitat identification
for prairie potholes 32
ii
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TABLES
1 Freshwater numeric aquatic life criteria 33
2 Suitability of wetland species to fill minimum
family requirements for six criterion chemicals 34
•»
3 Some conditions recommended for dilution water
for water quality criteria testing 35
4 Effects of cof actors on criterion chemical toxic ity 36
5 Water chemistry for selected Minnesota marshes 37
€ Comparison of test species with Minnesota marsh
biota for six criterion chemicals 38
7 Number of species tested for acute criteria and
percentage of test species that are not found in
Minnesota marshes or oligosaline prairie potholes 40
8 Water quality characteristics for oligosaline
prairie potholes 41
9 Comparison of test species with prairie pothole
biota for six criterion chemicals 42
111
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ACKNOWLEDGEMENTS
Preparation of this document has been funded by the U.S.
Environmental Protection Agency. This document has been prepared
at the EPA Environmental Research Laboratory in Duluth,
Minnesota, through Contract # 68033544 to AScI Corporation. This
document has been subjected to the Agency's peer and
administrative review. Excellent reviews and assistance were
received from C. Stephan, R. Spehar, *C. Johnston, E. Hunt, D.
Robb, and J. Minter.
IV
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SECTION 1
INTRODUCTION
NEED FOR STANDARDS FOR WETLANDS
Wetlands have been studied.and appreciated for a relatively
short time in relation to other types of aquatic systems. The
extent of their value in the landscape has only recently been
recognized; in fact, a few decades ago government policies
encouraged wetland drainage and conversion. Wetlands
traditionally have been recognized as important fish and wildlife
habitats, and it is estimated that over one-third of U.S.
endangered species require wetland habitat for their continued
existence. Some of their many other values, however, have become
apparent only recently. These include attenuation of flood
flows, groundwater recharge, shoreline and stream bank
stabilization, filtering of pollutants from point and nonpoint
sources, unique habitats for both flora and fauna, and
recreational and educational opportunities.1
Impacts to Wetlands
Despite new appreciation of the valuable functions that
wetlands perform in the landscape, they continue to be destroyed
and altered at a rapid pace. Since pre-settlement times over
half of the wetlands in the continental U.S. have been destroyed,
and losses over the last few decades have remained high.2 These
figures only represent actual loss of acreage and do not account
for alterations to or contamination of still-extant wetlands.
The causes of wetland destruction and degradation include:3
* Urbanization - Resulting in drainage and filling,
contamination, and ecological isolation of wetlands.
* Agriculture Conversion - Drainage, cropping, and
grazing which change or destroy wetland structure and
ecological function.
* Water Resource Development - Water flow alterations to
wetlands from diking, irrigation diversions,
alterations to rivers for navigation, diversions for
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water supply, and groundwater pumping. These result in
changes in the hydrology that sustains the wetland
system.
* Chemical Pollution - From point and nonpoint sources,
hazardous waste sites, mining, and other activities.
These can overwhelm the assimilative capacity of
wetlands or be toxic to wetland organisms.
* Biological Disturbances - Introduction or elimination
of plant and animal species that affect ecosystem
processes.
Gaps in Federal Regulatory Programs *.
Existing Federal regulatory programs intended to reduce some
of the impacts described above leave major gaps in the protection
of wetlands. Section 404 of the Clean Water Act (CWA) requires a
permit to be obtained from the Army Corps of Engineers, in
cooperation with the U.S. Environmental Protection Agency (EPA),
before dredged material or fill can be discharged into waters of
the United States. Alterations such as drainage, water
diversion, and chemical contamination are not covered by Section
404 unless material will be discharged into the wetland in
association with such alterations. The Resource Conservation and
Recovery Act, which regulates the disposal of hazardous wastes,
and the CWA, which regulates contamination from waste-water
discharges and nonpoint-source pollution, could provide
protection from certain impacts, but they have not been used
consistently to regulate impacts to wetlands. Programs designed
to protect endangered species, migratory birds, and marine
mammals have also been used to reduce impacts to wetlands, but
"the application of these programs also has been uneven."*
Gaps in State Regulatory Programs
. Wetland regulations vary greatly among states. Some States
are now developing narrative standards for wetlands (e.g.
Wisconsin, Rhode Island, and others). On the other hand,
although wetlands are included in the Federal definition of
"waters of the United States" and are protected by Section 101(a)
of the CWA, not all States include them as "waters of the State"
in their definitions. A review conducted in 1989 by the EPA
Office of Wetlands Protection and the Office of Water Regulations
and Standards found that only 27 of SO States mentioned wetlands
in definitions of State waters. The review verified that there
generally is a lack of consideration given to water quality
standards for wetlands.5
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Effective Use of Fxiatina Regulatory Options
Although some impacts (e.g. excavation, most drainage, and
destruction of vegetation) are not addressed by the current
implementation of existing regulations and programs, much of the
chemical contamination of wetlands could be controlled through
existing Federal and state water pollution control laws.* The
National Wetlands Policy Forum recommended that EPA and State
water pollution control agencies review the implementation of
their water quality programs to ensure that the chemical
integrity of wetlands is adequately protected. The Forum
stressed the need to develop water quality standards designed to
protect sensitive wetlands.
*
Under Section 401 of the CWA, States have authority to
authorize, condition, or deny all Federal permits or licenses in
order to comply with state water quality standards, including,
but not limited to, Sections 402 and 404 of the CWA, Sections 9
and 10 of the Rivers and Harbors Act, and Federal Energy
Regulatory Commission licenses, states with water quality
standards-that apply to or are specifically designed for wetlands
can use. 401 certification much more effectively as a regulatory
tool. •
As wetlands receive more recognition as important components
of State water resources, the need for testing the applicability
of some existing guidelines and standards to wetlands regulation
becomes more apparent.
PROPOSED APPROACH TO DEVELOPMENT OF WETLAND STANDARDS
The EPA Office of Water Regulations and standards and Office
of Wetlands Protection recently completed a document entitled,
"National Guidance: Water Quality standards for Wetlands."6 It
recommends a two-phased approach for the development of water
quality standards for wetlands. In the first 3-year phase of
this program, standards for wetlands would be developed using
existing information in order to provide protection to wetlands
consistent with the protection afforded other State waters.
Technical support for this initial phase will be provided through
documents such as this one, which focuses on the application of
existing numeric criteria to wetlands. These criteria are widely
used. Applying them to wetlands requires a small amount of
effort and can be accomplished quickly.
The development of narrative biocriteria is also required in
the initial phase of standards development. The long-term goal
(3-10 years) of this program is to develop numeric biocriteria
for wetlands. It is anticipated that both narrative and numeric
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biocriteria can provide a more integrative estimate of whole-
wetland health and better identification of impacts and trends
than can be attained by traditional numeric chemical criteria.
Field-based, community-level biosurveys can be implemented to
complement, and help validate, laboratory-based conclusions.
Results of such surveys can be used to monitor wetlands for
degradation and establish narrative or numeric biocriteria or
guidance which take into account "real world11 biological
interactions and the interactions of multiple stressors.
More information on the development of numeric biocriteria
will be available in a guidance document in coming years.
Technical guidance to support the development of biological
criteria for wetlands has also been prepared.7 This guidance
provides a synthesis of technical information on field studies of
inland wetland biological communities.
PURPOSE OF THIS DOCUMENT
A number of steps are needed to develop wetland standards.
The document, "National Guidance: Water Quality Standards for
Wetlands," mentioned above, provides general guidelines to the
States for each of the following steps: the inclusion of
wetlands in definitions of State waters, the relationship between
wetland standards and other water-related programs, use
classification systems for wetlands, the definition of wetland
functions and values, the applicability of existing narrative and
numeric water quality criteria to wetlands, and the application
of antidegradation policies to wetlands.
The technical document for biological criteria7 and this
report are companions to the guidance document described above.
This report is directed primarily toward wetland scientists
unfamiliar with water quality regulation and is intended to
provide a basis for dialogue between wetland scientists and
criteria experts regarding adapting numeric aquatic life criteria
to wetlands. More specifically:
1) It provides background information and an overview of
water quality standards and numeric chemical criteria, including
application to wetlands.
2) The need for evaluating numeric water quality criteria is
discussed. The site-specific guidelines are introduced and
discussed in two contexts: a) as an initial screening tool to
ensure that water quality in extreme wetland types is adequately
protected by criteria, and b) in terms of using the site-specific
guidelines to modify criteria for wetlands where criteria might
be over or underprotective.
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3) An approach is described that uses information available
from criteria documents and is designed to: a) detect wetland
types where water quality is not clearly protected by existing
criteria, and b) help prioritize further evaluations and research
efforts.
4) A simple test of the approach is presented with two
examples. Results are not considered conclusive and are
presented only as an example of the procedure.
Most of the data and examples are based on the freshwater
acute criteria. A similar approach should be equally applicable
to the saltwater acute criteria and to both saltwater and
freshwater chronic criteria.
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SECTION 2
CURRENT SURFACE WATER STANDARDS AND CRITERIA
This section describes how criteria are used in State
standards, how national numeric criteria are derived, and what
options are currently available for modifying national aquatic
life criteria.
DESCRIPTION OF STANDARDS AND CRITERIA
Surface waters are protected by Section 101(a) of the CWA
with the goal: "to restore and maintain the chemical, physical,
and biological integrity of the nation's waters." State water
quality standards are developed to meet this goal.
State Standards
There are two main components to establishing a standard:
1) The level of water quality attainable for a particular
waterbody, or the designated use of that waterbody (e.g.
recreational, fishery, etc.) is determined; 2) Water quality
criteria (usually a combination of narrative and numeric) are
established to protect that designated use. Water quality
standards also contain an antidegradation policy "to maintain and
protect existing uses and water quality, to provide protection
for higher quality waters, and to provide protection for
outstanding national resource waters."* State standards for a
particular waterbody must be met when discharging wastewaters.
The "National Guidance: Water Quality Standards for Wetlands"6
outlines a basic program to achieve these goals for wetlands.
Aquatic Criteria
Narrative Criteria—
Narrative criteria are statements, usually expressed in a
"free from ..." format. For example, all States have a narrative
statement in their water quality standards which requires that
their waters not contain "toxic substances in toxic amounts."
Narrative criteria are typically applied at the State level when
combinations of pollutants must be controlled or when pollutants
are present which are not listed in State water quality
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standards.8 States must document the process by which they
propose to implement these narrative criteria in their standards.
Numeric Criteria—
Pollutant-specific numeric criteria are used by the States
when it is necessary to control individual pollutants in order to
protect the designated use of a waterbody. Fate and transport
models commonly are used to translate these criteria into permit
limits for individual dischargers. Some criteria apply State-
wide and others are specific to particular designated uses or
waterbodies.
National numeric criteria are developed by EPA based on best
available scientific- information. They serve as recommendations
to assist States in developing their own criteria and to assist
in interpreting narrative criteria.9 These include human health
and aquatic life pollutant-specific criteria and whole effluent
toxicity criteria. Sediment criteria are now being developed.
States can adopt national numeric criteria directly.
Alternatively, site-specific criteria may be developed using EPA-
specified guidelines, and State-specific criteria can be derived
using procedures developed by the State.8
DEVELOPMENT OF NATIONAL AQUATIC LIFE NUMERIC CRITERIA
National aquatic life criteria are usually derived using
single-species laboratory toxicity tests. Tests are repeated
with a wide variety of aquatic organisms for each chemical. The
criteria are designed to protect against unacceptable effects to
aquatic organisms or their uses caused by exposures to high
concentrations for short periods of time (acute effects), to
lower concentrations for longer periods of time (chronic
effects), and to combinations of both.9 EPA criteria are
composed of 1) magnitude (what concentration of a pollutant is
allowable) ; 2) duration of exposure (the period of time over
which the in-stream concentration is averaged for comparison with
criteria concentrations); and 3) frequency (how often the
criterion can be exceeded without unacceptably affecting the
community).10 Separate criteria are determined for fresh water
and salt water. Field data are used when appropriate.
All acceptable data regarding toxicity to fish and
invertebrates are evaluated for inclusion in the criteria. Data
on toxicity to aquatic plants are evaluated to determine whether
concentrations of the chemical that do not cause unacceptable
effects to aquatic animals will cause unacceptable effects to
plants. Bioaccumulation data are examined to determine if
residues in the organisms might exceed FDA action levels or cause
known effects on the wildlife that consume them. For a complete
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description of the procedures for deriving ambient criteria,
consult the "National Guidelines'* (1985).*
Numeric water quality criteria are designed to protect most
of the species inhabiting a site.9 A wide variety of taxa with a
range of sensitivities are required for deriving criteria.
Guidelines are followed to determine the availability of
sufficient experimental data from enough appropriate taxa to
derive a criterion. For example, to derive a freshwater Final
Acute Value for a chemical, results of acute tests with at least
one species of freshwater animal in at least eight different
families are required. Acute and chronic values can be made to
be a function of a water quality characteristic such as Ph,
salinity, or hardness, when it is determined that these
characteristics impact toxicity, and enough data exist to
establish the relationship. Table 1 lists the chemicals for
which freshwater aquatic life criteria have been developed and
indicates which of those criteria are pH, hardness, or
temperature dependent.
SITE-SPECIFIC GUIDELINES
An option for modifying national aquatic life water quality
criteria to reflect local conditions is presented in the site-
specific guidelines. States may develop site-specific criteria
by modifying the national criteria for sites where 1) water
quality characteristics, such as pH, hardness, temperature, etc.,
that might impact toxicity of the pollutants of concern differ
from the laboratory water used in developing the criterion; or 2)
the types of organisms at the site differ from, and may be more
or less sensitive than, those used to calculate the criterion; or
3) both may be true, site-specific criteria take local
conditions into account to provide an appropriate level of
protection. They can also be used to set seasonal criteria when
there is high temporal variability.6
A testing program can be used to determine whether site-
specific modifications to criteria are necessary. This program
may include water quality sampling and analysis, a biological
survey, and acute and chronic toxicity tests.11 If site-specific
modifications are deemed necessary, 3 separate procedures are
available for using site-specific guidelines to modify criteria
values, including the recalculation procedure, the indicator
species procedure, and the resident species procedure. These
will be discussed more fully in the next section.
8
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SECTION 3
THE NEED FOR EVALUATING NUMERIC WATER QUALITY CRITERIA:
USE OF THE SITE-SPECIFIC GUIDELINES
OVERALL RELEVANCE OF CRITERIA TO WETLANDS
The national aquatic life criteria have been developed to
provide guidance to the States for the protection of aquatic life
and their uses in a variety of surface waters. They are designed
to be conservative and "... have been developed on the theory
that effects which occur on a species in appropriate laboratory
tests will generally occur on the same species in comparable
field situations. All North American bodies of water and
resident aquatic species and their uses are meant to be taken
into account, except for a few that may be too atypical ..,"9 A
wide variety of taxonomic groups sensitive to many materials are
used in testing, including many taxa common to both wetlands and
other surface waters. In order to ensure that criteria are
appropriately protective, water used for testing is low in
particulate matter and organic matter, because these substances
can reduce availability and toxicity of some chemicals. For
these reasons, the "National Guidance: Water Quality Standards
for Wetlands" states that, in most cases, criteria should be
protective of wetland biota.6
Although the water quality criteria are probably generally
protective of wetlands and provide the best currently available
tool for regulating contamination from specific pollutants, there
are many different types of wetlands with widely variable
conditions. There might be some wetland types where the resident
biota or chemical and physical conditions are substantially
different from what the criteria were designed to protect. These
differences could result in underprotection or overprotection of
the wetland resource. This section discusses the use of site-
specific guidelines for wetland types for which certain criteria
might be over or underprotective, but its primary focus is to
provide a mechanism to identify wetland types that might be
underprotected by certain criteria and that might require further
research.
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WETLAND VARIABILITY
Wetlands are usually located at the interface between
terrestrial systems and truly aquatic systems, and so combine
attributes of both.12 They are intermediate between terrestrial
and aquatic systems in the amount of water they store and process
and are very sensitive to changes in hydrology.12 Their chemical
and physical properties, such as nutrient availability, degree of
substrate anoxia, soil salinity, sediment properties, and pH are
influenced greatly by hydrologic conditions. Attendees at a
Wetlands Water Quality Workshop (held in Easton, Maryland in
August, 1988) listed the most common ways in which wetlands
differ from "typical" surface waters:_ higher concentrations of
organic carbon and particulate matter, more variable and
generally lower pH, more variable and generally lower dissolved
oxygen, more variable temperatures, and more transient
availability of water.13
There is also high variability among wetland types.
Wetlands, by definition, share hydrophytic vegetation, hydric
soils, and a water table at or near the surface at some time
during the growing season. Beyond these shared features,
however, there is tremendous hydrological, physical, chemical,
and biological variability. For example, an early
classification system for wetlands. "Circular 39", listed 20
distinctly different wetland types , and the present "Cowardin"
system lists 56 classes of wetlands.15 This variability makes it
important to evaluate different wetland types individually.
USE OF THE SITE-SPECIFIC GUIDELINES FOR WETLANDS
The site-specific guidelines outlined in Section 2 are
designed to address the chemical and biological variability
described above. Determining the need for site-specific
modifications to criteria requires a comparison of the aquatic
biota and chemical conditions at the site to those used for
establishing the criterion. This comparison is useful for
identifying wetland types that might require additional
evaluation. The three site-specific options are discussed in the
context of their general relevance to wetlands and are used in
this discussion to provide a framework for evaluating the
protectiveness of criteria for wetlands.
In most cases, because of the conservative approach used in
the derivation of the criteria, use of the site-specific
guidelines to modify criteria results in no change or fin their
relaxation, provided that an adequate number of species are used
in the calculations. However, criteria can also become more
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restrictive. Newly tested species could be especially sensitive
to certain pollutants, or extreme water conditions found in some
surface waters or wetland types might not reduce the toxicity of
a chemical. Disease, parasites, predators, other pollutants,
contaminated or insufficient food, and fluctuating and extreme
conditions might all affect the ability of organisms to withstand
toxic pollutants.9
Appropriateness of Testing Organisms • Recalculation Procedure
The first option given in the site-specific guidelines is
the recalculation procedure.8-11 This approach is designed to
take into account differences between the sensitivity of resident
species and those used to calculate a criterion for the material
of concern. It involves eliminating data from the criterion
database for species that are not resident at that site. It
could require additional resident species testing in laboratory
waiter if the number of species remaining for recalculating the
criterion drops below the minimum data requirements. "Resident"
species include those that seasonally or intermittently exist at
Use of the recalculation procedure will not necessarily
result in a higher acute criterion value (less restrictive) , even
it sensitive species are eliminated from the dataset and minimum
family requirements are met. The number of families used to
calculate Final Acute Values is important. If a number of non-
t?«tland species are dropped out of the calculation without adding
a sufficient number of new species, a lower (more restrictive)
Final Acute Value can result, because data are available for
species.11
Similarity of Required Taxa and Typical Wetland Species —
The variety of test species required to establish the
national numeric criteria was chosen to represent a wide range of
tasea having a wide range of habitat requirements and sensitivity
to toxicants. Establishment of a freshwater Final Acute Value
for a chemical requires a minimum of 8 different types of
families to be tested. These include: 1) the family Salmonidae;
2) a second family of fish, preferably a warmwater species; 3) a
third family in the phylum Chordata (fish, amphibian, etc.); 4) a
planktonic crustacean; 5) a benthic crustacean; 6) an insect; 7)
a family in a phylum other than Arthropoda or Chordata; and 8) a
family in any order of insect or phylum not already represented.9
When a required type of family does not exist at a site, the
guidelines for the recalculation procedure specify that
substitutes from a sensitive family, resident in the site, should
be added to meet the minimum family data requirement. Should it
happen that all resident families have been tested and the
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minimum data requirements still have not been met, the acute
toxicity value from the most sensitive resident family that has
been tested should be used as the site-specific value.
Most of the required families are probably well-represented
in most wetland types. Some types of wetlands, however, seldom
or never contain fish, and most wetland types do not support
salmonids or aquatic insects requiring flowing water.
General Evaluation of Species Suitability—
Table 2 presents six criterion chemicals chosen as examples
and the eight taxonomic groups required to establish criteria.
The chemicals include two organochlorines: polychlorinated
biphenyls (PCBs - used in industrial applications,
environmentally-persistent, bioaccumulate) and pentachlorophenol
(widely used fungicide and bactericide); one organophosphate:
parathion (insecticide); two metals: zinc and chromium(VI); and
cyanide.
The species used for acute toxicity testing for each of the
six chemicals have been broken down by taxonomic group and
evaluated based on the likelihood that those species can be found
in wetlands. Except for the unsuitability of the Salmonidae to
most wetland types, most of the taxonomic groups are well-
represented for the six chemicals used as examples. Wetland
species were not present in the list of species used to calculate
the Final Acute Value for the "non-arthropod/non-chordate" and
"another insect or new phylum" groups for a few of the criteria.
This is not because these groups are not represented in wetlands.
These are very general classifications. For example, the "non-
arthropod/non-chordate" group can include rotifers, annelids, and
mollusks among other phyla, all of which should have many
representatives in most types of wetlands. There is a large
degree of variation in the total number of species tested for the
six chemicals used as examples, ranging from 10 fish and
invertebrates for polychlorinated biphenyls (PCBs) to 45 for zinc
(Table 7). Criteria based on smaller numbers of species are less
likely to include a sufficient number of wetland species to
fulfill the minimum family requirements. Additional toxicity
testing, using laboratory water and wetland species from the
missing families, can be done to fill these gaps.
While the general taxonomic groups required for toxicity
testing are fairly well represented in wetlands, the similarity
between the genera and species inhabiting individual wetland
types and those used for criteria testing varies widely among
criteria and wetland types. Species chosen for toxicity testing
were seldom or never chosen with wetlands in mind. Intaddition,
relatively little is known about species assemblages in some
types of wetlands (particularly in those lacking surface waters,
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such as wet meadows or bogs). Defining typical wetland taxa is
difficult. For example, while most £xfifiS of wetlands do not
support salmonids, Coho salmon are highly dependent on wetlands
in Alaska, where there is a higher percentage and acreage of
wetlands than in any other State. Part of the utility of the
evaluation proposed here is in identifying where significant gaps
in data exist.
Influence of Cofactors: Indicator Species Procedure
The second of the three site-specific procedures, the
indicator species procedure, accounts for differences in
biological availability and/or toxicity of a material caused by
physical and/or chemical characteristics of the site water, or
cofactors. For the acute test, the effect of site water is
compared to the effect of laboratory water, using at least two
resident species or acceptable non-resident species (one fish and
one invertebrate) as indicators. A ratio is determined, which is
used to modify the Final Acute Value. See Carlson et al. (1984)
for information and guidelines for determination of site-specific
chronic values.11
Suitability of Standard Testing Conditions—
Standard aquatic toxicity tests are performed using natural
or reconstituted dilution water that should not of itself affect
the results of toxicity tests. For example, organic carbon and
particulate matter are required to be low to avoid sorption or
complexation of toxicants, which might lower the toxicity or
availability of some criterion chemicals. Recommended acute test
conditions for certain water quality characteristics of fresh and
salt water are listed in Table 3. Wetlands, as well as some
types of surface waters, can have values far outside the ranges
used for standard testing for some of these characteristics (most
notably total organic carbon, particulate matter, pH, and
dissolved oxygen). Wetland types can be evaluated to identify
these extremes.
Wetland Cofactors—
Many water quality characteristics can 1) act as cof actors
to affect the toxicity of pollutants (e.g. alkalinity/acidity,
hardness, ionic strength, organic matter, temperature, dissolved
oxygen, suspended solids); 2) can be directly toxic to organisms
(e.g. un-ionized ammonia, high or low pH, hydrogen sulfide, low
dissolved oxygen); or 3) can interfere mechanically with feeding
and reproduction (e.g. suspended solids). The criteria for some
of these water quality characteristics can be naturally exceeded
in many wetland types, as well as in some lakes and streams.
Hardness, pH, and temperature adjustments built into a few
of the criteria account for effects from these cof actors in a few
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cases, but no other cofactors are now included in the criteria,
despite some known effects. For example, alkalinity, salinity,
and suspended solids, in addition to pH and hardness, are known
to affect the toxicities of heavy metals and ammonia. These
cofactors are not included in the criteria primarily because
there are insufficient data.9 For example, most toxicity tests
have been performed under conditions of low or high salinity, so
that estuaries, where salinity values can vary greatly, may
require salinity-dependent site-specific criteria for some
metals.11 An initial evaluation of the adequacy of protection
provided to a wetland type by a criterion should take possible
cofactor effects into account.
t^oph iiiation i Resident Species Procedure
The resident species procedure accounts for differences in
both species sensitivity and water quality characteristics.11
This procedure is costly, because it requires that a complete
minimum dataset be developed using site water and resident
species. It is designed to compensate concurrently for
differences in the sensitivity range of species represented in
the dataset used to derive the criterion and for site water
differences which may markedly affect the biological availability
and/or toxicity of the chemical.11
AQUATIC PLANTS
One of the most notable differences between wetlands and
other types of surface waters is the dominance (and importance)
of aquatic macrophytes and other hydrophytic vegetation in
wetlands. Aquatic plants probably constitute the majority of the
biomass in most wetland types.
Few data concerning toxicity to aquatic plants are currently
required for deriving aquatic life criteria. Traditionally,
procedures for aquatic toxicity tests on plants have not been as
well developed as for animals. Although national numeric
criteria development guidelines state that results of a test with
a freshwater alga or vascular plant "should be available" for
establishing a criterion, they do not require that information.9
The Final Plant Value is the lowest (most sensitive) result from
tests with important aquatic plant species (vascular plant or
alga), in which the concentrations of test material were measured
and the endpoint was biologically important. Plant values are
compared to animal values to determine the relative sensitivities
of aquatic plants and animals. If plants are "among the aquatic
organisms that are most sensitive to the material," results of a
second test with a plant from another phylum are included.9
14
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Results of tests with plants usually indicate that criteria
which protect aquatic animals and their uses also protect aquatic
plants and their uses.9 As criteria are evaluated for their
suitability for wetlands, however, plant values should be
examined carefully. Additional plant testing may be advisable in
some cases. If site-specific adjustments are made to some
criteria, they could result in less restrictive acute and chronic
values for animals. Some plant values could then be as sensitive
or more sensitive than the animal values. Chemicals with fairly
sensitive plant values include: aluminum, arsenic(III), cadmium,
chloride, chromium(VI}, cyanide, and selenium(VI). For example,
fish are generally much more sensitive to cyanide than
invertebrates. If the recalculation procedure was used to
develop a site-specific cyanide criterion for a wetland type
containing no fish, values for these ''sensitive species would be
replaced in the calculation, possibly by less sensitive species.
A less restrictive criterion could result, possibly making the
plant value more sensitive than the animal value. Therefore,
additional consideration should be given to plant toxicity data
for wetland systems.
15
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SECTION 4
EVALUATION PROGRAM
The direct application of existing aquatic life criteria to
wetlands is assumed to be reasonable in most cases. It provides
a practical approach towards protecting the biological integrity
of wetlands. The following evaluation program offers a possible
strategy to identify extreme wetland -'types that might be
underprotected by some criteria, to prioritize wetland types and
criterion chemicals for further testing or research, and to
identify gaps in available data. The approach can be helpful for
identifying those instances where modifications to existing
criteria might be advisable. The proposed evaluation program
offers a screening tool to begin to answer the following
questions: 1) Are there some wetland types for which certain
criteria are underprotective? 2) For criteria in wetland types
that cannot be applied directly, can site-specific guidelines be
used to modify the criteria to protect the wetland? 3) Will
additional toxicity testing under wetland conditions and with
wetland species be necessary in some cases in order to establish
site-specific criteria?
The proposed approach relates species and water quality
characteristics of individual wetland types to species and water
quality characteristics important in deriving each criterion. It
involves identifying wetland types of concern, identifying
cofactors possibly affecting toxicity for the criteria of
interest, gathering data on the biota and water quality
characteristics of the wetland type, and comparing to data used
to derive the criterion*
CLASSIFICATION
The proposed program for the evaluation of the suitability
of aquatic life criteria discussed in this section can be done
separately for individual wetland types. These can be defined in
the classification process, which is the first step in developing
standards for wetlands. The classification process requires the
identification of the various structural types of wetlands and
identification of their functions and values.* The
classification should provide groups of wetlands that are similar
16
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enough structurally and functionally so that they can reasonably
be expected to respond in kind to inputs of toxic chemicals.
EVALUATING THE APPROPRIATENESS OF DIRECT APPLICATION OF CRITERIA
Information Needed
1. Identification of cofactors. Cofactors potentially
affecting mobility and biological availability for each criterion
chemical should be identified. Cofactors known to affect each
criterion chemical are listed in individual national criteria
documents and are summarized in Table 4. The absence of a
relationship between.a cofactor and a chemical on Table 4 does
not ensure that no relationship exists, merely that none was
discussed in the criteria document. The chemistry of the effects
of the cofactors on the chemicals is often very complicated, and
limited data are available regarding some of the relationships.
The approach presented here is simplistic and is geared toward
directing further efforts, other sources of information, in
addition to the criteria documents, should be consulted when
actually applying this approach. Criteria that include hardness-
or pH-dependent correction factors (Table 1) should apply
directly to wetlands unless the wetland type has extremes of pH
or hardness well outside the ranges used in toxicity testing.
For example, the pH of acid bogs can be as low as 3.5, well below
the 6.5 lower limit for toxicity testing (Table 3).
2. Comparison to wetland water chemistry* Natural levels
and variability of those cofactors should be identified as well
as possible for each major wetland type of interest. Wetlands*
related information can be accumulated through consultation with
wetland researchers, through literature searches, and from
monitoring agencies.
3. Comparison of species lists. Species lists of fish,
invertebrates, and plants should be compiled for each wetland
type and compared to lists of species used for testing each
criterion. Lists should be evaluated on two levels: a) Species
level - Are the species used for toxicity testing representative
(the same species or genera, or "similar" in terms of sensitivity
to toxicants) of the species found in the wetland type?
b) Family level - Does the wetland contain suitable
representatives for each of the families listed in the minimum
family requirements?8'11 Consultation with fish and invertebrate
specialists, plant ecologists, and wetlands experts will be
necessary to do this comparison.
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Adoption of ExisiHprf water Quality
The existing water quality criterion should be suitable for
that wetland type if the following are true:
1. Important cof actor levels are not naturally exceeded in
the wetland to a degree that might seriously affect toxicity or
availability of the chemical. Would toxicity likely be higher,
lower, or not influenced by typical levels or extremes of a
particular cof actor in a particular wetland type?
2. Sufficient species or genera used for aquatic toxicity
testing are found in the wetland type so that the minimum family
requirements can be met by resident wetland species.
Consultation between wetland scientists and criteria experts will
be necessary in many cases to make judgements on how well-
represented some wetland types are.
3. The criterion itself is not naturally exceeded in the
wetland.
DEVELOPING SITE-SPECIFIC CRITERIA
When one or more of these stipulations is not true or when
insufficient data are available, more evaluation is advisable.
Again, consultation between wetland scientists and criteria
experts might be helpful in prioritizing those wetland types for
which additional protection, or additional research, might be
needed for some chemicals. Once a priority list for further
evaluation is established, an approach to obtaining the
additional required data can be determined. It might be possible
to group wetlands by type, and possibly by designated use, and
then develop site-specific criteria for all wetlands of that type
in the State.
18
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SECTION 5
EXAMPLE ANALYSES
Evaluations of the applicability of the six criteria listed
in Table 2 will be made for two sets of wetland data, including
shallow marshes and prairie potholes. The analyses in these
examples were made with limited data for each wetland type and
are preliminary. They have been compiled to be used only as
illustrations of the usefulness of this approach.
EXAMPLE 1
The first example is based on a wetland study taking place
in southcentral Minnesota. The wetlands are being studied to
evaluate the effects of disturbance on water quality, as well as
the effects of pesticides on wetland communities. Therefore
chemical and biological data have been collected.18
Classification
The wetland study sites are primarily shallow marshes
(freshwater palustrine, persistent emergent, semi-permanently or
seasonally-flooded, according to Co war din15), dominated by
Phalaris (reed canary grass) and Typha (cattails), but also
include a small number of wet meadow/seasonally-flooded wetlands,
deep marsh, shrub/scrub + woody wetlands, and ponds.
steps 1 and 2: Identification of Cofactors and Comparison to
Wetland Water Chemistry
Cofactors are identified for criteria chemicals in Table 4.
Some water quality characteristics averaged for 5 seasons for the
Minnesota wetlands are summarized in Table 5.
Although some water chemistry conditions in the shallow
marshes were within the ranges of the aquatic toxicity testing
conditions, others were exceeded (Table 3). Wetland values for
pH were well within the 6.5-9.0 range allowed for testing, so
criteria having pH as a possible cofactor affecting toxicity
and/or biological availability should not be underprotective
because of pH effects. As Table 4 shows, PCP, chromium(VI),
zinc, and cyanide can be more toxic at low pH values, so a very
19
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acidic wetland might require additional evaluation in regard to
pH. The PCP criterion has an adjustment factor for pH, which
indicates that enough suitable data are available to allow this
relationship to be incorporated into the criterion.
Hardness values were not available for these marshes, but
were probably fairly low since alkalinity was low. Table 4 lists
hardness as a cofactor for zinc and chromium(VI). Table 1
reveals that the zinc criterion has an adjustment factor for
hardness, so any effect of hardness on zinc toxicity and/or
biological availability is already included in the criterion and
does not have to be considered further. Chromium(VI) is more
toxic at low alkalinity and hardness, but the criterion was
derived using soft water and should he protective for the
wetlands.
Total organic carbon (TOG) was highly variable in the
wetlands and generally well above the 5 mg/L limit for toxicity
testing. However parathion and zinc, the two criteria with TOG
cofactor effects, have reduced toxicity and/or biological
availability at high levels of organit matter (Table 4), so
criteria should be protective.
Dissolved oxygen (DO) was highly variable in the wetlands
and reached very low levels in late summer. The shallow waters
of the marshes were extremely warm on hot summer days. Toxicity
and/or biological availability is increased by low DO and high
temperatures for PCBs, PCP, and cyanide. These relationships
will require further evaluation.
Step 3: Comparisons of Species Lists
In Step 3, fish, invertebrates, and plants inhabiting the
wetlands are compared to species used in testing each criterion.
For these examples, only the acute toxicity lists have been
consulted. A list of genera common to both the marshes and to
the toxicity tests was compiled for each criterion. When
identical species were not found, species from the same genus
were compared to determine whether habitat requirements are
suitable enough to include them as representative species for
these wetlands. The shortened list of marsh species the same as,
or similar to, species used for toxicity testing was examined to
determine whether the minimum family requirements for acute
toxicity tests could be met for each criterion. Table 6 contains
a list of marsh genera that could be used to fulfill minimum
family requirements for each criterion. Appendix A contains a
list of the sources that have been consulted in making this
comparison.
20
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The aquatic species found in the Minnesota wetlands were
fairly veil-represented by the acute toxicity test species for
the six chemicals used in this example. The percentages of total
species tested that have not been found in these wetlands were
below 50% for all six criteria (Table 7). Except for PCBs, for
which no plant value is available, plant species tested
overlapped with species occurring in the wetlands. The absence
of salmonids in wetlands was the only consistent omission.
Of all the species tested, the salmonids are the most
sensitive to PCP and cyanide and are much more sensitive than
most invertebrate species. The inclusion of highly sensitive
salmonid data in the criteria calculations probably ensures that
these two criteria' are adequately protective when applied to
wetlands not containing this sensitive family (not considering
cofactor effects). It would perhaps be more important to
consider the effects of the absence of salmonids in Minnesota
marshes for criteria where salmonids are among the least
sensitive species, including parathion and chromium(VI). In this
case, the presence of salmonid toxicity data in the criterion
calculation, despite their absence from the wetlands, could
possibly cause the criterion to be less restrictive than is
appropriate for the wetland.
Salmonids do not occur in the wetlands included in this
example. Three criteria were missing an additional required
taxonomic group (from Table 6: PCBs, chromium(VI), and cyanide).
There are certainly representatives of this taxonomic group
(nonarthropod/nonchordate) inhabiting the wetlands, but the
genera used for toxicity tests did not correspond to the wetland
genera. These three criteria have the least species on the acute
toxicity list, so there are less species to compare to, in
relation to the other criteria (Table 7). Toxicity experts and
wetland biologists might be able to fill some of these data gaps
by reaching conclusions on the suitability of wetland species to
fulfill the minimum family requirements.
EXAMPLE 2
This example is based on data for a number of oligosaline
prairie pothole wetlands in southcentral North Dakota. w'w
Oligosaline is defined as ranging from 0.5-5 g/Jcg salinity, or
specific conductance of 800-8,000 nS/cm at 25°C."
The chemical types of the majority of wetlands used in this
example include magnesium bicarbonate, magnesium sulfate, and
sodium sulfate.20
21
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classification
wetlands included in this example are semipermanent (cover
type 4 of the classification system developed by Stewart and
Kantrud for the glaciated prairie region)2f, containing wet
meadow, shallow marsh, and deep marsh. Classification of these
wetlands based on the Cowardin system can be found in Kantrud et
al.20
Steps 1 and 2: Identification of Cofactors and Comparison to
Wetland Water Chemistry
Cofactors are identified for criteria chemicals in Table 4.
Water quality data for the prairie pfethole wetlands are
summarized in Table 8. A comparison of water chemistry
conditions for the prairie potholes with standard toxicological
testing conditions (Table 3) reveals a number of differences.
These wetlands are extremely alkaline and saline compared to
water used for freshwater toxicity testing. Salinity (reported
as specific conductance) can vary greatly over the year and is
concentrated by the high rates of evaporation and transpiration
that take place in the summer. A number of the wetlands have pH
values above the 6.5-9.0 range that the criteria are designed to
protect. No data were available for total organic carbon (TOC),
but dissolved organic carbon values from other prairie pothole
systems were generally well above the TOC limit of 5 mg/L used
for toxicity testing.22 As in Example 1, hardness can be
eliminated from consideration as a cofactor, because toxicity
and/or biological availability is decreased as hardness
increases. Similarly, the probable high TOC levels would
decrease toxicity and/or biological availability for zinc and
chromium(VI). The high pH values should cause decreased toxicity
and/or biological availability. Bioavailability of zinc is
reduced in high ionic strength waters such as these.
Dissolved oxygen (DO) levels drop in the winter and in
middle to late summer, allowing anoxic conditions to develop.
Although no aquatic temperature data were available, the Dakotas
have moderately hot summers (mean July temperature of 22.3°C).20
The shallow waters of the prairie potholes probably become very
warm in late summer, corresponding with low DO levels. Toxicity
and/or biological availability is increased by low DO and high
temperatures for PCBs, PCP, and cyanide. These relationships
will require further evaluation.
step 3; Comparisons of Species Lists
- - -- •- •• •- f.
Semi-permanent prairie pothole wetlands are generally
shallow and eutrophic. Water levels fluctuate greatly, as does
22
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salinity. The cold winters can cause some of the wetlands to
freeze to the bottom. Both winter-Kill and summerkill, caused by
the effects of lack of oxygen, can occur. Fish can survive only
in semipermanent wetlands that have connections to deeper water
habitat. The only native fishes known to occur in semi-permanent
prairie potholes are fathead minnow fPimenhales prone 1 as i and
brook stickleback fCulaea
The invertebrate taxa of prairie potholes are typical of
other eutrophic, alkaline systems in the United States.
Macroinvertebrate species assemblages are highly influenced by
hydroperiod and salinity in these systems, and species diversity
drops as salinity increases.20 Care must be taken in aggregating
large salinity ranges into one wetland type (i.e. "oligosaline"
may ba too broad a class in terms of species representativeness) .
Comparisons of species typical of the wetlands with the criteria
species lists reveals some major differences. For example, a
large proportion of the aquatic insects tested for each criterion
are found in flowing water, and therefore might not be
characteristic of prairie pothole aquatic inspects. Although many
species of aquatic insects are found. in these* wetlands20, there
are not many suitable aquatic insects on the criteria species
lists to compare to resident wetland species. Prairie pothole
wetlands do not harbor Decapods (crayfish and shrimp) , another
common group for testing. Eubranchiopods (fairy, tadpole, and
clam shrimp) are commonly found in prairie pothole wetlands20,
but only one representative of this group has been used to
establish criteria, and that species was not on the list for any
of the criteria used as examples here. Except for PCBs, for
which no plant value is available, plant species tested do
overlap with species occurring in the wetlands. Appendix B
contains sources used in making comparisons.
The above discussion has obvious implications for
determining applicability of criteria based on suitability of
species. As Table 7 shows, the percentages of species tested for
each criterion that have not been found in prairie potholes are
rather high (up to 67%) . There are more gaps in the minimum
family requirements for fish and chordates (Table 9) than were
found for the Minnesota marsh example. The lack of fish in these
wetlands dictates that amphibians or other chordates be used to
fill these family requirements. The paucity of fish in these
wetlands again has relevance to the protectiveness of the
criteria. Fish are the most sensitive group tested for PCP and
cyanide, so these criteria may have an added "buffer" of
protection (in relation to the other criteria used as examples)
when applied with no modifications to this wetland type.
23
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SUMMARY OF THE EXAMPLE ANALYSES
The conclusions discussed below should be considered as
examples only. They should not be considered final for these
wetland types.
Cofactor Effects
Based on this simple analysis, the only cofactors that
potentially could cause criteria to be underprotective were DO
and temperature. The low DO and high temperatures common in both
wetland types in mid to late summer could cause increased
toxicity and/or biological availability for PCBs, PCP, and
cyanide. Cofactor effects for chromium(VI}, zinc, and parathion
were either not important under the chemical conditions
encountered in these wetlands or should result in criteria being
more, rather than less, protective for the wetland biota. Based
on water quality characteristics, it can be concluded that
chromium(VI), zinc, and parathion criteria are probably
adequately protective of these wetland types with no acute
modification.
The importance of the DO and temperature relationship
requires further evaluation for PCBs, PCP, and cyanide. Chemists
and wetlands experts should be consulted and further literature
reviews should be completed to evaluate the need for additional
toxicity tests. If it is determined that a modification to a
criterion is warranted, seasonal site-specific criteria might be
appropriate in this case. The indicator species procedure could
be used, requiring toxicity tests using site water on one fish
and one invertebrate. The tests could be done at the high
temperatures and low DO found in late summer in the wetlands.
Species Comparisons
The Salmonidae are a required family group for establishing
a Final Acute Value and yet are not present in either of the
wetland types used as examples. This evaluation is most
concerned with ensuring that criteria are adequately protective,
so the absence of this family in the wetlands should only be
considered a problem if the unmodified criterion (which includes
the Salmonidae) might be underprotective. This would most likely
be true for parathion and chromium(VI).
For several criteria, some family requirements are not
fulfilled because the available toxicity data for that taxonomic
group do not include wetland species or genera ("NT" in Tables 6
and 9). While this document made comparisons at the genus level,
others have made comparisons at the family level to determine if
the species listed in the criteria document is a member of a
24
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family that exists at the site.16 Issues related to species
comparisons should be addressed through discussion with criteria
experts and wetlands ecologists and through further literature
review.
The absence of fish in prairie potholes to fill the "other
chordates11 category for cyanide, zinc, chromium(VI), and PCBs may
warrant additional toxicity tests and site-specific
modifications. The only other fish likely to be present in these
wetlands is the brook stickleback (Culaea inconstansl20 which was
not tested for any of the six criteria. No non-fish chordates
were tested either, so no evaluation of the probable sensitivity
of other chordates to these criteria can be made based on the
criteria documents^
If it is decided upon more rigorous evaluation that these
differences in taxonomic groups warrant additional efforts and
development of site-specific criteria, the recalculation
procedure can be used. A suitable family, resident in the
wetlands, can be added to the list to replace the Salmonidae
and/or other missing groups, either through additional toxicity
tests or by including additional available data.
Further Evaluation
This approach helps to prioritize wetland types and criteria
for further evaluation. It was concluded that zinc,
chromium(VI), and parathion criteria require no modification with
regard to cofactor effects. PCBs, PCP, and cyanide, however,
should be evaluated further in regard to the effects of high
temperatures and low DO on toxicity, for both wetland types. The
absence of salmonids may be most important for parathion and
chromium(VI) in both wetland types. Further consideration should
be given to the need for additional tests with chordates from
prairie pothole wetlands for cyanide, zinc, chromium(VI) and
PCBs, although there is no evidence to suggest that the absence
of representative wetland chordates from the test species will
result in underprotective criteria.
This type of evaluation, done for a number of wetland types
and criteria, can be combined with information on the types of
pollutants that threaten particular wetland types. In this way
wetland types requiring additional evaluation and perhaps
eventually some additional toxicity testing for particular
pollutants can be prioritized based on adequacy of existing
criteria, potential threats to the system, and resources
available for testing. These examples illustrate the need for
wetland scientists to work closely with criteria experts. Expert
judgement is needed to evaluate the significance of the gaps in
the available data.
25
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SECTION 6
CONCLUSIONS
The efficient use of limited resources dictates that
criteria and standards for wetlands be developed by making good
use of the wealth of data that has been accumulated for other
surface waters. This report focused ,on the application of
numeric aquatic life criteria to wetlands. The numeric aquatic
life criteria are designed to protect aquatic life and their
uses. The criteria are conservative, and for most wetland types
are probably protective or overprotective.
A simple, inexpensive evaluation technique has been proposed
in this document for detecting wetland types that might be
underprotected for some chemicals by existing criteria. The
approach relies on information contained in criteria documents,
data regarding species composition and water quality
characteristics for the wetland types of interest, and
consultation with experts. It is intended to be used as a
screening tool for prioritizing those wetland types that require
additional evaluations and research.
Two tests of the approach demonstrated that it can be used
to identify cases in which criteria might be underprotective, but
further evaluation and close coordination among regulatory
agencies, wetland scientists, and criteria experts are needed to
determine when actual modifications to the criteria are
necessary.
Site-specific guidelines for modifying the numeric criteria
should be appropriate for use on wetlands in cases where
additional evaluations reveal that modifications are needed. The
approach described in this document can be used to compile lists
of the most commonly under-represented species and the most
frequently encountered chemicals. Aquatic toxicity tests can
then be conducted which would apply to a number of wetland types.
Information obtained with this approach can be used to
prioritize further evaluations and research, identify gaps in
data, and make further testing more efficient, but has some
limitations. It does not adequately address the importance of
plants in wetland systems and applies only to the aquatic
component of wetlands. It relies on species assemblage and water
26
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quality data that are not available for some wetland types. For
these reasons, a meeting of wetland scientists and criteria
experts is recommended to discuss the need for this type of
evaluation, the utility of this approach, and possible
alternative approaches.
The application of numeric criteria to wetlands is just one
part of a large effort to develop wetland standards and criteria.
The development of biocriteria, sediment criteria, and wildlife
criteria will help to ensure that all components of the wetland
resource are adequately protected.
27
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REFERENCES
1. U.S. Fish and Wildlife Service. 1984. An Overview of Major
Wetland Functions and Values.
2. Tiner, R.W., Jr. 1984. Wetlands of the United States:
Current Status and Recent Trends. U.S. Fish and Wildlife
Service. • .
3. U.S. EPA, Office of Water. 1989. The Water Planet.
4. The Conservation Foundation. 1988. Protecting America's
Wetlands: An Action Agenda: The Final Report of the
National Wetlands Policy Forum.
5. U.S. EPA, Office of Water Regulations and Standards, Office
of Wetlands Protection. 1989. Survey of State Water
Quality Standards for Wetlands. Internal report.
6. U.S. EPA, Office of Water Regulations and Standards, Office
of Wetlands Protection. In Review. Draft National
Guidance: Water Quality Standards for Wetlands.
7. Adamiis, P.R., K. Brandt, and M. Brown. 1990. Use of
Biological Community Measurements for Determining Ecological
Condition of, and Criteria for, Inland Wetlands of the
United States - A Survey of Techniques, Indicators,
Locations, and Applications. U.S. EPA, Corvallis, Oregon.
8. U.S. EPA, Office of Water Regulations and Standards. 1986.
Quality Criteria for Water. EPA-440/5-86-001. U.S. EPA,
Washington, D.C.
9. Stephan, C.E., D.I. Mount, D.J. Hansen, J.H. Gentile, G.A.
Chapman, and W.A. Brungs. 1985. Guidelines for Deriving
Numerical National Water Quality Criteria for the Protection
of Aquatic Organisms and Their Uses. PB85-227049. National
Technical Information Service, Springfield, Virginia.
10. U.S. EPA, Office of Water. 1985. Technical Support
Document for Water Quality-based Toxics Control. EPA-440/4-
85-032.
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11. Carlson, A.R., W.A. Brungs, G.A. Chapman, and D.J. Hansen.
1984. Guidelines for Deriving Numerical Aquatic Site-
Specific Water Quality criteria by Modifying National
Criteria. EPA-600/3-84-099. U.S. EPA, Duluth, Minnesota.
12. Mitsch, W.J. and J.G. GosselinJc. 1986. Wetlands. New
York: Van Nostrand Reinhold.
13. Phillip, K. 1989. Review of Regulated Substances and
Potential Cofactors in Wetland Environments. Draft internal
report submitted to U.S. EPA.
14. Shaw, S.P., and C.G. Fredine. 1956. Wetlands of the United
States, Their- Extent, and Their Value for Waterfowl and
Other Wildlife. U.S. Fish and* Wildlife Service, Circular
39. Washington, D.C., 67p.
15. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe.
1979. Classification of Wetlands and Deepwater Habitats of
the United States. FWS/OBS-79/31. U.S. Fish and Wildlife
Service.
16. Hansen, D.J., J. Cardin, L.R. Goodman, and G.M. Cripe.
1985. Applicability of Site-Specific Water Quality Criteria
Obtained Using the Resident Species Recalculation Option.
Internal report, U.S. EPA, Narragansett, Rhode Island and
Gulf Breeze, Florida.
17. American Society for Testing Materials. 1988. Standard
Guide for Conducting Acute Toxicity Tests with Fishes,
Macroinvertebrates, and Amphibians. Standard E 729-88a,
ASTM, Philadelphia, Pennsylvania.
18. Detenbeck, N.E. 1990. Effects of Disturbance on Water-
Quality Functions of Wetlands: Interim Progress Report:
January 1990. Natural Resources Research Institute.
Internal report submitted to U.S. EPA, Duluth, Minnesota.
19. Swan son, G.A., T.C.* Winter, V.A. Adomaitis, and J.W.
LaBaugh. 1988. Chemical Characteristics of Prairie Lakes
in South-central North Dakota - Their Potential for
Influencing Use by Fish an Wildlife. U.S. Fish and Wildlife
Service Technical Report 18.
20. Kantrud, H.A., G.L. Krapu, and G.A. Swanson. 1989. Prairie
Basin Wetlands of the Dakotas: A Community Profile. U.S.
Fish and Wildlife Service Biological Report 85(7.28).
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21. Stewart, R.E., and H.A. Kantrud. 1971. Classification of
Natural Ponds and Lakes in the Glaciated Prairie Region.
U.S. Fish and Wildlife Service Resource Publication 92
57p.
22. LaBaugh, J.W. 1989. Chemical Characteristics of Water in
Northern Prairie Wetlands. Pages 56-90 In A.G. van der
Valk, ed., Northern Prairie Wetlands. Iowa State University
Press.
30
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APPENDIX A
SOURCES USED IN SPECIES HABITAT IDENTIFICATION
FOR MINNESOTA MARSHES
Fishes:
Eddy, S., and J.C. Underbill.-. 1974. Northern Fishes. 3rd
edition. University of Minnesota, Minneapolis.
Nelson, J.S. 1984. Fishes of the World. 2nd edition. New
York: John Wiley and Sons.
Niering, W.A. 1987. Wetlands. New York: Alfred A. Knopf.
Personal Communications:
P. DeVore and C. Richards of the Natural Resources
Research Institute, Duluth, Minnesota.
G. Mont2, Minnesota Dept. of Natural Resources.
Macroinvertebrates:
Niering, W.A. 1987. Wetlands. New York: Alfred A. Knopf.
Pennak, R.W. 1978. Fresh-water Invertebrates of the United
States. 2nd edition. New York: John Wiley and Sons.
Williams, w.D. 1976. Freshwater Isopods (Asellidae) of
North America. U.S. EPA, Cincinnati.
Personal Communications:
P. DeVore and A. Kershey of the Natural Resources
Research Institute, Duluth, Minnesota.
P. Mickelson of the University of Minnesota, Duluth.
31
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APPENDIX B
SOURCES USED IN SPECIES HABITAT IDENTIFICATION
FOR PRAIRIE POTHOLES
Fishes:
Kantrud, H.A., G.L. Krapu, and G.A. Svanson. 1989. Prairie
Basin Wetlands of the Dakotas: "A Community Profile. U.S.
Fish and Wildlife Service Biological Report 85(7.28).
Swanson, G.A., T.C. Winter, V.A. Adomaitis, and J.W.
LaBaugh. 1988. Chemical Characteristics of Prairie Lakes
in South-central North Dakota - Their Potential for
Influencing Use by Fish an Wildlife. U.S. Fish and wildlife
Service Technical Report 18.
Macroinvertebrates:
Broschart, M.R. and R.L Linder. 1986. Aquatic
invertebrates in level ditches and adjacent emergent marsh
in a South Dakota wetland. Prairie Nat. 18(3):167-178.
Eddy, S. and A.C. Hodson. 1961. Taxonomic Keys to the
Common Animals of the Northcentral States. Minneapolis:
Burgess Publishing Co.
Krapu, G.L. 1974. Feeding ecology of pintail hens during
reproduction. The Auk 91:278-290.
Pennak, R.W. 1978. Fresh-water Invertebrates of the United
States. 2nd edition. New York: John Wiley and Sons.
Swanson, G.A. 1984. Invertebrates consumed by dabbling
ducks (Anatinae) on the breeding grounds. Journal of the
Minnesota Academy of Science 50:37-45.
van der Valk, A., ed. 1989. Northern Prairie Marshes.
Ames: Iowa State University Press.
32
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TABLE 1. FRESHWATER NUMERIC AQUATIC LIFE CRITERIA*
Chemical
H, T, or pH*
Dependent
Chemical
H, T, or pH"
Dependent
Organochlorines:
Aldrin
Chlordane
DDT
Dieldrin
Endosulfan
Endrin
Heptachlor
Lindane
PCBs
Pentachlorophenol
Organophosphates:
Chlorpyrifos
Parathion
pH
Metals:
Aluminum
Arsenic(III)
Cadmium H
Chromium(III) H
Chromium(VI)
Copper H
Lead H
rMercury
Nickel H
Selenium
Silver H
Zinc H
Others:
Ammonia pH, T
Chloride
Chlorine
Cyanide
Dissolved oxygen T
* Summarized from individual criteria documents. Chemicals
that have adjustment factors built into the criteria are
indicated.
** H = Hardness, T = Temperature.
33
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TABLE 2. SUITABILITY OF WETLAND SPECIES TO FILL MINIMUM FAMILY
REQUIREMENTS FOR SIX CRITERION CHEMICALS
Required
Taxonomic
Group
Salmon id
Other Fish
Other
Chordate
Planktonic
Crustacean
Benthic
Crustacean
Insect
Nonarthropod-
Nonchordate
Another
Insect
or New Phylum
PCBs
NP*
Y"
Y
•
Y
Y
Y
NT*"
Y
Para-
thion
NP
Y
Y
Y
Y
Y
Y
Y
PCP
NP
Y
Y
\
Y
Y
Y
Y
Y
Cyanide
NP
Y
Y
Y
Y
A
Y
Y
NT
Zinc
NP
Y
Y
Y
Y
Y
Y
Y
Chrom-
ium (VI)
NP
Y
Y
Y
Y
Y
Y
Y
*NP Not present: Taxonomic group not present in most wetland
types.
**Y Wetland genera represented adequately.
***NT Not tested: Available toxicity data does not include
sufficient wetland species.
34
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TABLE 3. SOME CONDITIONS RECOMMENDED FOR DILUTION WATER
FOR WATER QUALITY CRITERIA TESTING17
Characteristic
Total organic carbon
Part icul ate matter
PH
Freshwater
<5 mg/L
-------
TABLE 4. EFFECTS OF COFACTOR8 OH CRXTERIOV CHEMICAL TOZZCZTT
COFACTORS: Effect of Gr«*t«r Valu«
TOG TURB TEMP DO H IOHIC 8 NUTR/ORO
Org&nochlorines:
Aldrin
Chlordane
DDT
Dieldrin
Endrin
Heptachlor
Lindane
Endosulfan
PCBs
Pentachlorophenol
Toxaphene
Organophosphates:
Parathion
Chlorpyrifos
Metala:
Arsenic (III)
Cadmium
Chromium (VI)
Chromium (III)
Copper
Lead
Mercury
Nickel
Selenium
Silver
Zinc
Aluminum
Other:
Chlorine
Cyanide
Ammonia
Chloride
DO
+ +
? 0
+
+?
0
-?
•y
0
+: increased toxicity/mobility
Oi no effect on toxicity/mobility
-: decreased toxicity/mobility
TOC: total organic carbon
TURB: turbidity
IONIC: ionic strength/cations
?: tested and found inconclusive
: not discussed in criteria document
±: short-term increase/long-term decrease
DO: dissolved oxygen H: hardness
NUTR/ORG: nutrients/organic acids
S: salinity
36
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TABLE 5. WATER CHEMISTRY FOR SELECTED MINNESOTA MARSHES*
,._ Comparison with
Water Quality Standard Testing
Characteristic Mean Value Range Conditions
pH (pH units) 7.1 6.1-7.6 Within range
Total organic
carbon (mg/L) 20 5-60 High
Dissolved
oxygen (mg/L) 8.2 0.4-15.4 Seasonally low
Hardness No data
(mg/L as CaCO3)
Alkalinity 8 4-14
(mg/L as CaCO})
Temperature (°C) 11.9 0.3-31.0 Seasonal extremes
Turbidity (NTU) 33 1 - 412
* Data taken from Detenbeck (1990), n=42 wetlands.10
37
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TABLE 6. COMPARISON OF TEST SPECIES WITH
MINNESOTA MARSH BIOTA FOR SIX CRITERIA
Required
Taxonomic
Group
Salmonid
Other Fish*
Other
Chordate
PCBS
NPd
Micropterus
Pimephales
Parathion
NP
Lepomis
Pimephales
PCP
NP
Micropterus
Rana
Planktonic
Crustacean
Benthic
Crustacean
Insect
Nonarthropod-
Nonchordate
Another
Insect
or New Phylum
Aquatic
Plant
Daphnia
unknown
amphipod
Ishnurab
NT*
Tanytarsus
NT
Daphnia
Orconectes
Chironomus
unknown0
nematodes/
annelids
Ishnura
alga
Daphnia
Orconectes
Tanytarsus
unknown6
nematodes/
annelids
unknown
amphipod/
isopod
Lemna
continued
38
-------
TABLE 6, CONTINUED
Required
Taxonomic
Group
Salmonid
Other Fish*
Other
Chordate
Cyanide
NP
Perca
Lepomis
Zinc
NP
Lepomis
Pimephales
Chromium (VI)
NP
Lepomis
Pimeohales
PlanJctonic
Crustacean
Benthic
Crustacean
Insect
Nonarthropod-
Nonchordate
Another
Insect
or New Phylum
Aquatic
Plant
Daphnia
unknown6
amphipod/
isopod
Tanytarsus
Physa
NT
Lemna
''Daphnia
unknown*
amphipod/
isopod
Argiab
Physa
unknown0
annelid/
nematode
Lemna
Daphnia
Orconectes
*
Chironomus
Physa
NT
alga
a Fish were sampled in water bodies associated with some of
the wetlands, not in the wetlands themselves.
b Probable or seen as an adult.
c Unknown species from these taxa found in wetlands. May or
may not be similar in terms of habitat requirements, etc. to
species used in toxicity tests.
d Not present: Taxonomic group not present in wetland type.
e Not tested: Available toxicity data does not include
sufficient wetland species.
39
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TABLE 7. NUMBER OF SPECIES TESTED FOR ACUTE CRITERIA AND
PERCENTAGE OF TEST SPECIES THAT ARE NOT FOUND IN
MINNESOTA MARSHES OR OLIGOSALINE PRAIRIE POTHOLES*
Species Used to Not Present Not Present in
Chemical Establish FAV** in Marshes Prairie Potholes
(Total Number} (Per cent) (Per cent)
PCBS
Parathion
PCP
Cyanide
Zinc
Chromium (VI)
10
37
37
17
45
33
30%
43%
22%
29%
45%
27%
40%
64%
43%
65%
67%
64%
* Remainder of nei-eentaoe includes both tho«e «rusr>ie«a that are
known to occur in these wetlands and those species that may
occur in the wetlands, but insufficient data are available.
** Final Acute Value.
40
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TABLE 8. WATER QUALITY CHARACTERISTICS. FOR
OLIGOSALINE PRAIRIE POTHOLES*
Water Quality
Characteristic
Mean Value
Comparison with
Standard Testing
Range Conditions
pH (pH units) 8.9
Total organic
carbon (mg/L) No datac
Dissolved
oxygen (ppm) . No datad
Hardness No data*
(mg/L as CaCO3)
Alkalinity 650
(mg/L as CaCO3)
Temperature (°C) No data*
Specific conductance 3568
(/iS/cm at 25°C)
7.4 - 10.3'
High
230 - 1300
High
750 - 8000
a
b
c
d
e
t
Data summarized from Swanson et al. (i988).19
N=27 wetlands.
Dissolved organic carbon data for Manitoba prairie potholes
ranged from 0.4-102 mg/L, and for Nebraska, from 20-60 mg/L
in one study and 139-440 mg/L in another study.22
Winterkill, caused by low dissolved oxygen under ice, occurs
in many of these lakes.
An estimate of hardness based on alkalinity values gives a
mean of 760 mg/L as CaCO,.
Region is characterized by very cold winters and warm
summers.
41
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TABLE 9. COMPARISON OF TEST SPECIES WITH
PRAIRIE POTHOLE BIOTA FOR SIX CRITERIA
Required
Taxonomic
Group
Salmonid
Other Fish
Other
Chorda te
Planktonic
Crustacean
Benthic
Crustacean
PCBs
NP
Pimephales
NT
Oaphnia
Gammarus'
Parathion
NP
Pimephales
Pseudacris*
\
Daphnia
Gammarus'
PCP
NP
Pimephales
Rana*
Daphnia
Hyalella
Insect
Nonarthropod-
Nonchordate
Another
Insect
or New Phylum
Aquatic
Plant
damselfly5
NT
Tanytarsusb
NT
Peltodytes
>
tubificid
wormb
Chironomus
Tanytarsus6
tubificid
wormb
Physa
Microcystis Lemna
42
-------
TABLE 9, CONTINUED
Required
Taxonomic
Group
Salmonid
Other Fish
other
Chordate
Cyanide
NP
Pimephales
NT
Zinc
NP
Pimephales
NT
Chromium (VI)
NP
Pimephales
NT
Planktonic
Crustacean
Benthic
Crustacean
Insect
Nonarthropod-
Nonchordate
Another
Insect
or New Phylum
Aquatic
Plant
Daphnia
Gammarus*
Tanytarsusb
Physa"
NT
Lemna
Oaphnia
Gammarus'
Argiab
Physa"
tubificid
worm6
Lemna
Daphnia
Hyalella
Chironomus1
Physa"
damselfly5
Nitzschia
a Genus is present in the wetlands; may not be same species.
b Species representative of that taxonomic group from criteria
testing lists probably present in prairie potholes, but no
actual data available.
43
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